CN210525761U

CN210525761U - Internal circulation mold closing device

Info

Publication number: CN210525761U
Application number: CN201921449850.4U
Authority: CN
Inventors: 李建军; 陈军寿; 蒋涛; 王岳鹏; 谭万红; 白春光
Original assignee: Guangdong Bloomachine Co ltd
Current assignee: Guangdong Bloomachine Co ltd
Priority date: 2019-09-03
Filing date: 2019-09-03
Publication date: 2020-05-15
Anticipated expiration: 2029-09-03

Abstract

The utility model discloses an inner loop MOLD CLAMPING APPARATUS, including compound die hydro-cylinder, auxiliary cylinder, mould moving oil cylinder, fixed die plate and movable mould board. The mould moving oil cylinder is used for providing power for driving the movable mould plate to move, a first channel is arranged between the mould closing oil cylinder and the auxiliary oil cylinder, so that the mould closing oil cylinder forms internal circulation work, namely when the movable mould plate moves, hydraulic oil can be in a rod cavity in the work of the mould closing oil cylinder, and quick circulation movement is carried out between the rodless cavity in the work and the auxiliary oil cylinder, so that the required power of the auxiliary movable mould plate in the moving process is provided, the energy consumption and the processing cost are reduced, the mould closing efficiency is improved, meanwhile, whether the valve is opened or closed can be realized by controlling oil feeding of the central hole and the outer hole in the mould closing oil cylinder, so that whether the rod cavity and the rodless cavity are communicated or not, the mould closing oil cylinder is suitable for different work requirements such as mould locking and mould closing in the.

Description

Internal circulation mold closing device

Technical Field

The utility model belongs to the technical field of the injection molding machine design and specifically relates to an inner loop MOLD CLAMPING APPARATUS is related to.

Background

An injection molding machine is a key device in plastic molding processing, the existing injection molding machine usually utilizes hydraulic oil as a power transmission medium, and a mold closing device is a key component in the injection molding machine and determines the work efficiency of mold locking and mold closing of the injection molding machine.

The existing common injection molding machine mold closing device can only supplement or discharge hydraulic oil inside through an external hydraulic system when in work, the mold closing device of the mode has high setting requirement of the external hydraulic system, and the circulation of the hydraulic oil needs to be recycled through an external oil way firstly, so that the circulation speed is low, the switching efficiency of mold locking and mold closing is high, the processing efficiency is influenced, meanwhile, the energy loss is large, and the processing cost is increased in a phase-changing manner.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an inner loop MOLD CLAMPING APPARATUS can solve one or more of above-mentioned problem.

According to one aspect of the utility model, an internal circulation mold closing device is provided, including compound die hydro-cylinder, auxiliary cylinder, shifting die hydro-cylinder, fixed die plate, movable die plate and oil pipe, the compound die hydro-cylinder includes compound die hydro-cylinder body, compound die piston rod, compound die piston, valve and piston end cover, the one end of compound die piston rod is connected with the compound die piston, the compound die piston is installed in the compound die hydro-cylinder body, and separates the compound die hydro-cylinder body inside for work has the pole chamber and does not have the pole chamber, valve one end is connected with the compound die piston rod, and the other end is connected with the piston end cover, the compound die piston is connected with the piston end cover, be equipped with the centre bore in the oil pipe, oil pipe is equipped with the outer orifice outward, oil pipe is connected with the valve, centre bore and outer orifice all are linked together with the, the valve is used for controlling the communication state of the working rod cavity and the working rodless cavity, the auxiliary oil cylinder, the mold moving oil cylinder and the mold closing oil cylinder body are all connected with the fixed template, the auxiliary oil cylinder, the mold moving oil cylinder and the mold closing piston rod are all connected with the movable template, the auxiliary oil cylinder is provided with an auxiliary rod cavity and an auxiliary rodless cavity, a first channel is arranged in the fixed template, and the auxiliary rod cavity is communicated with the working rod cavity through the first channel.

The utility model has the advantages that: the utility model discloses in, the mould moving oil cylinder is used for providing the power that the drive movable mould board removed, and then through setting up first passageway between compound die hydro-cylinder and the auxiliary cylinder, make it form inner loop work, when the movable mould board is when removing, hydraulic oil can have the pole chamber in the work of compound die hydro-cylinder, carry out quick circulation between work rodless chamber and the auxiliary cylinder and remove, demand power when providing supplementary movable mould board and removing, the consumption and the processing cost of energy reduction, and improve compound die efficiency, and simultaneously, can be through the oil feed of control centre bore and outer hole in the compound die hydro-cylinder, realize opening or closing of valve, thereby realize whether the intercommunication that work has pole chamber and work rodless chamber, with the mode locking that adapts to the in-process of moulding plastics, different work needs such as compound die, therefore, the clothes hanger is strong in practicability, and good stability.

In some embodiments, the number of the die closing cylinders is three, the number of the auxiliary cylinders is one, a second channel is arranged in the fixed die plate, and working rod cavities of adjacent die closing cylinders are communicated through the second channel. The arrangement of the plurality of die-closing oil cylinders can improve the moving stability of the movable die plate, and the working rod cavities of the adjacent die-closing oil cylinders are communicated, so that the internal circulation work of the plurality of die-closing oil cylinders and the auxiliary oil cylinder can be realized.

In some embodiments, the sum of the volumes of the working rod chambers of the three clamp cylinders plus the volume of the auxiliary rod chamber of the auxiliary cylinder is equal to the sum of the volumes of the working rodless chambers of the three clamp cylinders. Therefore, hydraulic oil can be ensured to be fully circulated between the multiple die closing oil cylinders and the auxiliary oil cylinder, and the phenomenon that the hydraulic oil cannot be fully circulated in the die closing oil cylinders to cause errors in die closing or die locking is avoided.

In some embodiments, the utility model discloses still include the connecting pipe, adjacent the compound die hydro-cylinder body of compound die hydro-cylinder is connected through the connecting pipe, and is adjacent the no pole chamber of work of compound die hydro-cylinder is linked together through the connecting pipe. When hydraulic oil in a working rod cavity in a certain die closing oil cylinder flows into the corresponding working rodless cavity, the flow rate of the hydraulic oil is larger than that of other die closing oil cylinders, the working rodless cavity is easily damaged, and the working rodless cavities among the die closing oil cylinders are communicated, so that the working rodless cavities with the excessive flow rate overflow into other working rodless cavities, and the working reliability of the die closing oil cylinders is improved.

In some embodiments, the valve includes a valve core and a valve body, one end of the valve body is connected with the mold closing piston rod, the other end of the valve body is connected with the piston end cover, the valve core is installed in the valve body, the oil pipe is connected with the valve core, a protrusion is arranged in the valve body, a backspacing cavity is enclosed by the protrusion and the valve core, the backspacing cavity is communicated with the central hole, a valve cavity is arranged in the valve body and is communicated with the outer hole, a limiting end is arranged on the valve body, when the valve core is contacted with the limiting end, the working rod cavity and the working rodless cavity are separated, and when the valve core is separated from the limiting end, the working rod cavity and the working rodless cavity.

In some embodiments, the mold closing piston is provided with a first hole, the mold closing piston rod is provided with a second hole, the valve body is provided with a fourth hole, the working rod cavity, the first hole, the second hole and the fourth hole are sequentially communicated, the piston end cover is provided with a first opening, the valve body is provided with a second opening, and the working rodless cavity, the first opening and the second opening are sequentially communicated. The setting in first hole can avoid the compound die piston to hydraulic oil endless hindrance, and the setting in second hole can avoid the compound die piston rod to hydraulic oil endless hindrance, and the valve body can be avoided to hydraulic oil endless hindrance to fourth hole and second open-ended setting, and the piston end cover can be avoided to hydraulic oil endless hindrance to first open-ended setting.

In some embodiments, the mold closing cylinder comprises a nozzle tip, an end cover and a gland, the end cover is connected with the other end of the mold closing piston rod, the nozzle tip is connected with the oil pipe, the nozzle tip is communicated with the central hole, the end cover is communicated with the outer hole, and the gland is connected with the end cover. The structure can facilitate the communication between the central hole and the outer hole and an external hydraulic system, so as to control the work of the central hole and the outer hole.

In some embodiments, the auxiliary oil cylinder comprises an auxiliary oil cylinder body, an auxiliary piston rod and an auxiliary piston, the auxiliary oil cylinder body is connected with the fixed die plate, the auxiliary piston rod is connected with the movable die plate, one end of the auxiliary piston rod is connected with the auxiliary piston, and the auxiliary piston is installed in the auxiliary oil cylinder body and divides the interior of the auxiliary oil cylinder body into an auxiliary rod cavity and an auxiliary rodless cavity. Therefore, the auxiliary piston can move in the auxiliary oil cylinder body, and the auxiliary piston rod can follow the auxiliary piston rod.

In some embodiments, the mold-moving oil cylinder comprises a mold-moving oil cylinder body, a mold-moving piston rod and a mold-moving piston, the mold-moving oil cylinder body is connected with the fixed mold plate, the mold-moving piston rod is connected with the movable mold plate, one end of the mold-moving piston rod is connected with the mold-moving piston, and the mold-moving piston is installed in the mold-moving oil cylinder body. Therefore, the mold moving piston can move in the mold moving oil cylinder body, and the mold moving piston rod is made to follow.

In some embodiments, the utility model discloses still include the guide rail, be equipped with the slider on the movable mould board, the slider suit is on the guide rail. The guide rail can be used as the guide of the motion of the movable template, and the moving dislocation of the movable template during the motion is reduced.

Drawings

Fig. 1 is a schematic structural diagram of an internal circulation mold clamping device according to an embodiment of the present invention.

Fig. 2 is a front view of a schematic configuration of an internal circulation mold clamping device of fig. 1.

Fig. 3 is a sectional view at B-B of a schematic configuration of an internal circulation mold clamping apparatus of fig. 2.

Fig. 4 is an enlarged view of a schematic diagram of an internal circulation mold clamping device of fig. 3 at C.

Fig. 5 is an enlarged view of a schematic diagram of an internal circulation mold clamping device of fig. 3 at D.

Fig. 6 is an enlarged view of a schematic view of an inner circulation mold clamping device of fig. 4 at E.

Fig. 7 is a sectional view at a-a of a schematic configuration of an internal circulation mold clamping apparatus of fig. 2.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 1 to 7, the internal circulation mold closing apparatus of the present invention includes a mold closing cylinder 10, an auxiliary cylinder 20, a mold moving cylinder 30, a fixed mold plate 40, a movable mold plate 50, and a connecting pipe 60.

The number of the die closing oil cylinders 10 is three, and each die closing oil cylinder 10 comprises a die closing oil cylinder 1, a die closing piston rod 2, a die closing piston 3, a valve 4, a piston end cover 5, an oil pipe 211, an oil nozzle 6, an end cover 7 and a gland 8. One end of the die closing piston rod 2 is fixedly connected with the die closing piston 3, the other end of the die closing piston rod is fixedly connected with the end cover 7, the die closing piston 3 is movably arranged in the die closing oil cylinder body 1, so that the die closing piston 3 can move in the die closing oil cylinder body 1, and the arranged die closing piston 3 divides the interior of the die closing oil cylinder body 1 into a working rod cavity 101 and a working rodless cavity 102. A central hole 200 is formed in the oil pipe 211, an outer hole 212 is formed outside the oil pipe 211, one end of the oil pipe 211 is fixedly connected with the oil nozzle 6, and the oil nozzle 6 is communicated with the central hole 200. The die closing piston 3 is fixedly connected with a piston end cover 5, the valve 4 is positioned between the die closing piston 3 and the piston end cover 5, one end of the valve is fixedly connected with the die closing piston 3, the other end of the valve is fixedly connected with the piston end cover 5, the gland 8 is fixedly connected with the end cover 7, the end cover 7 is communicated with the outer hole 212, the oil nozzle 6 is positioned in the end cover 7, and a hole communicated with the oil nozzle 6 is reserved on the gland 8.

The valve 4 comprises a valve core 41 and a valve body 42, one end of the valve body 42 is fixedly connected with the matched mold piston rod 2, the other end of the valve body 42 is fixedly connected with the piston end cover 5, the valve core 41 is movably arranged in the valve body 42, so that the valve core 41 can move in the valve body 42, the other end of an oil pipe 211 in the matched mold piston rod 2 is fixedly connected with the valve core 41, the oil pipe 211 extends into the valve core 4 and is fixedly connected with the inside of the valve core 41, a protrusion 4201 is arranged in the valve body 42, the protrusion 4201 and the valve core 41 enclose a retraction cavity 4202, corresponding holes are arranged on the side portion of the valve core 42, the retraction cavity 4202 and a valve cavity 4203 are separated by the valve core 41, the central hole 200 is communicated with the retraction cavity 4202 through the holes, the.

The mold closing piston 3 is provided with a first hole 310, the mold closing piston rod 2 is provided with a second hole 210, the valve body 42 of the valve 4 is provided with a fourth hole 421, and the working rod cavity 101, the first hole 310, the second hole 210 and the fourth hole 421 are communicated in sequence. The piston end cover 5 is provided with a first opening 510, the valve body 42 of the valve 4 is provided with a second opening 422, and the working rodless cavity 102, the first opening 510 and the second opening 422 are communicated in sequence. And the valve body 42 is provided with a limit end 420, when the outer hole 212 is filled with oil, the valve cavity 4203 is filled with oil, so that the valve core 41 is pushed in the valve body 42 toward the direction close to the limit end 420 until the valve core 41 contacts the limit end 420, the second opening 422 and the fourth hole 421 are separated by the valve core 41, that is, the working rod cavity 101 and the working rodless cavity 102 are separated, when the central hole 200 is filled with oil, the retraction cavity 4202 is filled with oil, so that the valve core 41 is pushed in the valve body 42 toward the direction away from the limit end 420, until the valve core 41 is separated from the limit end 420, the second opening 422 and the fourth hole 421 are communicated, that is, the working rod cavity 101 and the working rodless cavity 102 are communicated, therefore, the central hole 200 and the outer hole 212 are used for controlling the opening and closing of the valve 4, and the valve 4 is used for controlling the communication state of the working rod cavity 101 and the working rodless cavity 102.

The auxiliary cylinder 20 is one, and the auxiliary cylinder 20 includes an auxiliary cylinder body 21, an auxiliary piston rod 22, and an auxiliary piston 23. One end of the auxiliary piston rod 22 is fixedly connected with the auxiliary piston 23, the auxiliary piston 23 is movably installed in the auxiliary cylinder 21, so that the auxiliary piston 23 can move in the auxiliary cylinder 21, and the auxiliary piston 23 divides the inside of the auxiliary cylinder 21 into an auxiliary rod chamber 201 and an auxiliary rodless chamber 202.

The number of the mold-moving oil cylinders 30 is two, and each mold-moving oil cylinder 30 comprises a mold-moving oil cylinder body 31, a mold-moving piston rod 32 and a mold-moving piston 33. One end of the mold-moving piston rod 32 is fixedly connected with the mold-moving piston 33, and the mold-moving piston 33 is movably installed in the mold-moving oil cylinder 31, so that the mold-moving piston 33 can move in the mold-moving oil cylinder 31.

The oil cylinder bodies 21 of all the auxiliary oil cylinders 20, the mould moving oil cylinder bodies 31 of all the mould moving oil cylinders 30 and the mould closing oil cylinder bodies 1 of all the mould closing oil cylinders 10 are fixedly connected with the fixed mould plate 40, three mould closing oil cylinders 10 and one auxiliary oil cylinder 20 are placed in an approximately square form after the mould closing oil cylinders are arranged, a first channel 401 and a second channel 402 are arranged in the fixed mould plate 40, an auxiliary rod cavity 201 in each auxiliary oil cylinder 20 is communicated with a working rod cavity 101 in two adjacent mould closing oil cylinders 10 through the first channel 401, and the working rod cavities 101 in the two adjacent mould closing oil cylinders 10 are communicated through the second channel. And the two arranged mold-moving oil cylinders 30 are arranged diagonally and symmetrically. The auxiliary piston rods 22 of all the auxiliary cylinders 20, the mold moving piston rods 32 of all the mold moving cylinders 30 and the mold closing piston rods 2 of all the mold closing cylinders 10 are fixedly connected with the movable mold plate 50. In addition, the sum of the volumes of the working rod chambers 101 of the three mold clamping cylinders 10 plus the volume of the working rod chamber 201 of the assist cylinder 20 is equal to the sum of the volumes of the working rodless chambers 102 of the three mold clamping cylinders 10, the mold clamping cylinder bodies 1 of adjacent mold clamping cylinders 10 are connected by a connecting pipe 60, and the working rodless chambers 102 of adjacent mold clamping cylinders 10 are connected by a connecting pipe 60.

The utility model discloses still include guide rail 70, be equipped with slider 501 on the movable mould board 50, slider 501 suit is on guide rail 70, and slider 501 can remove along guide rail 70, and guide rail 70, compound die hydro-cylinder 10's compound die piston rod 2, auxiliary cylinder 20's auxiliary piston rod 22 and the equal parallel arrangement of mould moving piston rod 32 that moves mould hydro-cylinder 30.

The utility model discloses when using, the supplementary rodless chamber 202 of auxiliary cylinder 20 is linked together with outside atmosphere, and glib 6 and the end cover 7 of each compound die hydro-cylinder 10 are equallyd divide and do not are connected with outside hydraulic system for the central oilhole 200 and the outer orifice 212 of each compound die hydro-cylinder 10 can carry out oil feed and oil return to it as required, and move the mould hydro-cylinder 30 and also link to each other with outside hydraulic system.

When the utility model is used for mold closing, the working rodless cavity 102 of each mold closing cylinder 10 can be filled with hydraulic oil, then the external hydraulic system drives the mold moving cylinder 30 to work, namely the mold moving piston rod 32 of the mold moving cylinder 30 pulls the movable mold plate 50 to move towards the direction of the fixed mold plate 40, at the same time, the central oil hole 200 in each mold closing cylinder 10 takes oil, and each outer hole 212 returns oil, then the corresponding valve core 41 is pushed in the valve body 42 towards the direction away from the limit end 420, so that the corresponding valve core 41 is separated from the limit end 420, namely, the working rod cavity 101 in each mold closing cylinder 10 is communicated with the working rodless cavity 102, so that the hydraulic oil in the working rodless cavity 102 of each mold closing cylinder 10 can flow into each working rod cavity 101, and a part of the hydraulic oil entering the working rod cavity 101 can also flow into the auxiliary rod cavity 201 of the auxiliary cylinder 20 through the first channel 401, realize the inner loop of hydraulic oil, at this moment, compound die piston rod 2 and auxiliary piston rod 22 can move along with the removal that moves mould piston rod 32 unhindered ground, and the inner loop work of hydraulic oil also can provide certain power, then the utility model discloses realize compound die work.

When the utility model discloses when being used for the mode locking, then outside hydraulic system no longer drives the work of mould moving hydro-cylinder 30, and simultaneously, outside hydraulic system is towards the outer hole 212 oil feed in each compound die hydro-cylinder 10, and each central oilhole 200 oil return, then correspond case 41 and can be promoted toward being close to spacing end 420 direction in valve body 42, make and correspond case 41 and spacing end 420 contact, then each work has between pole chamber 101 and the corresponding work rodless chamber 102 to be cut off by the case, hydraulic oil can't have the circulation between pole chamber 101 and the work rodless chamber 102 in work, then outside hydraulic system has pole chamber 101 interior high-pressure hydraulic oil of input to work, in order to establish the clamping force, make the utility model discloses realize the mode locking work.

When the utility model discloses when being used for the die sinking, the supplementary pole chamber 201 that has of auxiliary cylinder 20 and the work of each compound die hydro-cylinder 10 have the pole chamber 101 in can having hydraulic oil to fill, then outside hydraulic system drive moves mould hydro-cylinder 30 work, move mould piston rod 32 that moves mould hydro-cylinder 30 and promote movable mould board 50 towards keeping away from the direction removal of fixed mould board 40 court simultaneously, the central oilhole 200 oil feed in each compound die hydro-cylinder 10 this moment, and each outer hole 212 oil return, then it can be in valve body 42 toward keeping away from spacing end 420 direction and promoted to correspond case 41, make and correspond case 41 and spacing end 420 and separate, work in each compound die hydro-cylinder 10 has pole chamber 101 and work no pole chamber 102 between communicate, the hydraulic oil that makes the work of each compound die hydro-cylinder 10 have pole chamber 101 can flow in each work no pole chamber 102, and the hydraulic oil in the supplementary pole chamber 201 of auxiliary cylinder 20 can flow to each work through first passageway 401 again in the work that the work in the compound die hydro-cylinder 10 has the pole chamber 101 and flows In the pole chamber 102, realize the inner loop of hydraulic oil, at this moment, compound die piston rod 2 and auxiliary piston rod 22 can move along with the removal that moves mould piston rod 32 unhindered, and the inner loop work of hydraulic oil also can provide certain power, then the utility model discloses realize the die sinking work, in addition, because be linked together through connecting pipe 60 between each work rodless chamber 102, from this, flow to hydraulic oil can realize the homogenization in each work rodless chamber 102 to guarantee the stability of its inner loop.

What has been described above are only some embodiments of the invention. For those skilled in the art, without departing from the inventive concept, several modifications and improvements can be made, which are within the scope of the invention.

Claims

1. An internal circulation mold closing device is characterized by comprising a mold closing oil cylinder (10), an auxiliary oil cylinder (20), a mold moving oil cylinder (30), a fixed mold plate (40) and a movable mold plate (50), wherein the mold closing oil cylinder (10) comprises a mold closing oil cylinder body (1), a mold closing piston rod (2), a mold closing piston (3), a valve (4), a piston end cover (5) and an oil pipe (211), one end of the mold closing piston rod (2) is connected with the mold closing piston (3), the mold closing piston (3) is installed in the mold closing oil cylinder body (1) and divides the interior of the mold closing oil cylinder body (1) into a working rod cavity (101) and a working rodless cavity (102), one end of the valve (4) is connected with the mold closing piston rod (2), the other end of the valve is connected with the piston end cover (5), the mold closing piston (3) is connected with the piston end cover (5), a central hole (200), an outer hole (212) is arranged outside the oil pipe (211), the oil pipe (211) is connected with the valve (4), the central hole (200) and the outer hole (212) are both communicated with the valve (4), the central hole (200) and the outer hole (212) are used for controlling the opening and the closing of the valve (4), the valve (4) is used for controlling the communication state of the working rod cavity (101) and the working rodless cavity (102), the auxiliary oil cylinder (20), the mould moving oil cylinder (30) and the mould closing oil cylinder body (1) are all connected with a fixed template (40), the auxiliary oil cylinder (20), the mould moving oil cylinder (30) and the mould closing piston rod (2) are all connected with the movable mould plate (50), the auxiliary oil cylinder (20) is provided with an auxiliary rod cavity (201) and an auxiliary rodless cavity (202), a first channel (401) is arranged in the fixed die plate (40), and the auxiliary rod cavity (201) is communicated with the working rod cavity (101) through the first channel (401).

2. An internal circulation mold clamping device as claimed in claim 1, characterized in that the mold clamping cylinders (10) are three, the auxiliary cylinder (20) is one, a second passage (402) is provided in the stationary platen (40), and the working rod chambers (101) of the adjacent mold clamping cylinders (10) are communicated with each other through the second passage (402).

3. An internal-circulation mold clamping apparatus as claimed in claim 2, wherein the sum of the volume of the working rod chambers (101) of the three mold clamping cylinders (10) plus the volume of the auxiliary rod chamber (201) of the auxiliary cylinder (20) is equal to the sum of the volumes of the working rodless chambers (102) of the three mold clamping cylinders (10).

4. An internal-circulation mold clamping apparatus according to claim 3, characterized by comprising a connecting pipe (60), wherein the mold clamping cylinder bodies (1) of adjacent mold clamping cylinders (10) are connected through the connecting pipe (60), and the working rodless chambers (102) of adjacent mold clamping cylinders (10) are communicated through the connecting pipe (60).

5. An internal circulation mold clamping device according to claim 1, characterized in that the valve (4) comprises a valve core (41) and a valve body (42), one end of the valve body (42) is connected with the mold clamping piston rod (2), the other end of the valve body (42) is connected with the piston end cover (5), the valve core (41) is installed in the valve body (42), the oil pipe (211) is connected with the valve core (41), a bulge (4201) is arranged in the valve body (42), the bulge (4201) and the valve core (41) enclose a backset cavity (4202), the backset cavity (4202) is communicated with the central hole (200), a valve cavity (4203) is arranged in the valve body (42), the valve cavity (4203) is communicated with the outer hole (212), a limit end (420) is arranged on the valve body (42), and when the valve core (41) is contacted with the limit end (420), the working rod cavity (101) and the working rodless cavity (102) are isolated, when the valve core (41) is separated from the limiting end (420), the working rod cavity (101) is communicated with the working rodless cavity (102).

6. An internal circulation mold closing device according to claim 5, characterized in that a first hole (310) is formed in the mold closing piston (3), a second hole (210) is formed in the mold closing piston rod (2), a fourth hole (421) is formed in the valve body (42), the working rod cavity (101), the first hole (310), the second hole (210) and the fourth hole (421) are sequentially communicated, a first opening (510) is formed in the piston end cover (5), a second opening (422) is formed in the valve body (42), and the working rodless cavity (102), the first opening (510) and the second opening (422) are sequentially communicated.

7. An internal circulation mold closing device according to claim 5, characterized in that the mold closing oil cylinder (10) comprises an oil nozzle (6), an end cover (7) and a gland (8), the end cover (7) is connected with the other end of the mold closing piston rod (2), the oil nozzle (6) is connected with an oil pipe (211), the oil nozzle (6) is communicated with the central hole (200), the end cover (7) is communicated with the outer hole (212), and the gland (8) is connected with the end cover (7).

8. An internal-circulation mold clamping device according to claim 1, characterized in that the auxiliary cylinder (20) comprises an auxiliary cylinder body (21), an auxiliary piston rod (22) and an auxiliary piston (23), the auxiliary cylinder body (21) is connected with the fixed platen (40), the auxiliary piston rod (22) is connected with the movable platen (50), one end of the auxiliary piston rod (22) is connected with the auxiliary piston (23), and the auxiliary piston (23) is installed in the auxiliary cylinder body (21) and divides the interior of the auxiliary cylinder body (21) into an auxiliary rod-containing cavity (201) and an auxiliary rodless cavity (202).

9. The internal circulation mold clamping device is characterized in that the mold moving oil cylinder (30) comprises a mold moving oil cylinder body (31), a mold moving piston rod (32) and a mold moving piston (33), the mold moving oil cylinder body (31) is connected with the fixed mold plate (40), the mold moving piston rod (32) is connected with the movable mold plate (50), one end of the mold moving piston rod (32) is connected with the mold moving piston (33), and the mold moving piston (33) is installed in the mold moving oil cylinder body (31).

10. An internal circulation mold clamping device according to claim 1, characterized by comprising a guide rail (70), wherein the movable mold plate (50) is provided with a slide block (501), and the slide block (501) is sleeved on the guide rail (70).